Conventionally, a printing method using an ink jet recording system is performed by flying ink droplets to deposit the ink droplets onto a recording medium, such as paper. Further, in recent years, with the advance of an ink jet recording system technology, an ink jet recording apparatus using an ink jet recording system has been used, even in the field of high-definition image recording (image printing) having used photographic or offset printing.
Ink jet recording, for example, as disclosed in JP-A-11-166143, is even used in dyeing (printing) a fabric. It is disclosed in the technology described in JP-A-11-166143 that, when the printing of a fabric is performed by an ink jet system, thixotropic properties are imparted by adding a salt of carboxymethyl cellulose to ink, and image sharpening is obtained by reducing the bleeding of edges of a pattern formed on the fabric.
However, generally, an ink jet ink used in ink jet recording is required to decrease the viscosity thereof to some degree in order to fly ink droplets by ejecting the ink droplets from thin ink flow channels or fine nozzles. Therefore, in the case of blending a polymer compound with the ink, when increasing the blending amount or molecular weight of the polymer compound in order to exhibit desired performance, there were cases where the viscosity of the ink increased.
Further, generally, in the case of an ink containing a pigment, a polymer compound is added for the purpose of dispersion of the pigment or for the purpose of improving the fixability of the pigment onto a medium, in addition to being added to suppress the bleeding of the ink. Therefore, even in the case of blending the polymer compound for fixing the pigment, the polymer compound is selected in consideration of the kind and blending amount thereof such that the viscosity of the ink does not excessively increase.
Meanwhile, it has been found that good surface gloss can be obtained when applying a cellulose-based polymer onto a medium, such as paper, composed of cellulose as a main component, and that good pigment fixability can be expected when blending the cellulose-based polymer with an aqueous pigment ink. However, as described above, from the request of suppressing the viscosity of the ink, it has been difficult to blend the cellulose-based polymer with the aqueous pigment ink in a high content.
One object according to some aspects of the present invention is to provide an ink composition for ink jet recording, which can be stably ejected by an ink jet recording apparatus, and which can exhibit good pigment fixability, high-quality recording, and good storage stability.